Deleuze and Guattari write, “Spinoza is the Christ of philosophers, and the greatest philosophers are hardly more than apostles who distance themselves or draw near this mystery.” If Spinoza is the Christ among Deleuze's philosophers, then Bergson is the Father, and Nietzsche the Holy Ghost. Spinoza offers us immanence, difference made flesh. Bergson offers us the temporality of duration, without which immanence cannot be born. And the spirit of Nietzsche, of the active and the creative affirmation of difference without recoupment into some form of identity, pervades the entire project.

Deleuze writes of other thinkers. There are books on Hume, Kant, Proust, Sacher-Masoch, Kafka, Foucault, and Leibniz. There are appeals to Lucretius, Scotus, and Heidegger, allusions to Melville, Henry Miller, Michel Tournier, Pierre Klossowski, Joyce, and scientific references to Monod and Prigogine. But in the end, there are three who stand above the others. It is they who provide the motivation and the framework for the ontologies Deleuze constructs over the course of his many writings. Immanence, duration, affirmation: Spinoza, Bergson, Nietzsche. These are the parameters of an ontology of difference.

Immanence is the first requirement of an ontology of difference. Philosophy cannot admit transcendence without lapsing into inadequate concepts, concepts of identity, concepts that ultimately lead us to conformism. “We must draw up a list of … illusions and take their measure, just as Nietzsche, following Spinoza, listed the ‘four great errors.’ But the list is infinite.